KR0164011B1 - Microwave densitometer - Google Patents

Abstract

A phase difference detection circuit for detecting a phase difference between a microwave generated by the microwave generator and a microwave received by the microwave receiver; and a phase difference detection circuit for detecting a phase difference in an apparent phase range varying in an angular range of 360 degrees from a minimum angle, fallen below the rotation number updating section and the reference phase difference θ ₁ and the apparent phase difference θ ₂ 'and the number of true phase difference θ ₂ and the reference phase difference in n rotation θ ₁ corresponds to the reference fluid for changing the value of the number of revolutions came back toward the maximum angle n and , A signal conversion circuit for converting the phase difference ?? into a density signal representing the concentration of the fluid to be measured, an operation mode setting unit in which the operation mode is set, and an operation mode setting unit for setting the operation mode set in the operation mode setting unit When the concentration of the fluid to be measured is changed from the measurement operation to the non-measurement operation in response to the change of the number of rotations n and A phase difference θ ₂ 'on the view shows a microwave meter, in which the hold-and-hold circuit.

Description

Microwave density meter

FIG. 1 is a configuration diagram of a microwave concentration meter according to an embodiment of the present invention; FIG.

FIG. 2 is a functional block diagram of a phase difference correction circuit. FIG.

FIG. 3 is a flow chart showing a part of the measurement operation of the microwave concentration meter according to the embodiment; FIG.

4 is a flow chart showing the remaining part of the measurement operation of the microwave densitometer.

FIG. 5 is a flow chart of the operation of updating the number of revolutions of the microwave density meter according to the embodiment; FIG.

6 is a flow chart for discriminating the density validity of the microwave density meter according to the embodiment.

Figure 7 shows the upper range and the lower range set in the measurement range of 0 ° to 360 °.

FIG. 8 is a graph showing a calibration curve graph. FIG.

9A is a view showing a state in which a reference fluid is filled in a measurement tube;

9B is a view showing a state in which the measuring tube is charged with the measured fluid.

10 shows the principle of an ultrasonic concentration meter.

FIG. 11 is a principle view of a microwave concentration meter. FIG.

FIG. 12 is a diagram for explaining a phase delay. FIG.

13 shows a diagram showing the failure by phase delay rotation;

FIG. 14 shows a zero point drift. FIG.

The present invention relates to a concentration meter capable of measuring the concentration of a suspended substance (for example, sludge, pulp, and other substances) contained in a fluid and the concentration of various dissolved substances dissolved in a fluid, and more particularly, The present invention relates to a microwave furnace densitometer capable of reliably measuring the concentration of suspended matter and the like over a wide concentration measuring range up to a wide range.

A densitometer for measuring the concentration of a fluid to be measured using ultrasonic waves is known. The principle of measurement of a conventional ultrasonic densitometer will be described with reference to FIG. The ultrasonic concentration meter typically has an ultrasonic transmitter 2 and an ultrasonic receiver 3 arranged so as to be opposed to the fluid to be measured on the pipe wall of the pipe 1. An ultrasonic oscillator 4 is connected to the ultrasonic transmitter 2 and an ultrasonic attenuation rate measuring circuit 5 is connected to the ultrasonic receiver 3.

In this ultrasonic concentration meter, an ultrasonic wave is emitted from the ultrasonic transmitter 2 to the ultrasonic receiver 3 in response to input of the ultrasonic signal from the ultrasonic oscillator 4 to the ultrasonic transmitter 2. Ultrasonic waves propagating through the fluid in the pipe 1 are received by the ultrasonic receiver 3. [ The intensity of the ultrasonic waves propagating in the liquid is attenuated according to the concentration of suspended matter present in the fluid.

The ultrasonic receiver (3) converts the attenuated ultrasonic wave into an electric signal in accordance with the reception intensity, and sends out the electric signal to the ultrasonic attenuation rate measuring circuit (5). In this attenuation ratio measuring circuit 5, a calibration curve defining the concentration of the suspended substance and the relationship with the ultrasonic receiver is set. The attenuation ratio measuring circuit 5 converts the ultrasonic reception intensity into a concentration in accordance with the calibration curve.

However, since the ultrasonic concentration meter described above must contact the transceivers 2 and 3 with the liquid flowing in the piping 1, it is necessary that the suspended substances are easily attached to the contact surfaces and cleaned periodically. Particularly, when a fluid such as sewage sludge flows, the possibility that the suspended material adheres increases.

Therefore, an ultrasonic concentration meter having a structure in which a suspended substance does not adhere has been devised. In this ultrasonic wave concentration meter, the ultrasonic transceivers 2 and 3 are attached to the outside of the pipe 1. However, this type of ultrasonic concentration meter has a problem in terms of strength and durability because the thickness of the wall of the pipe 1 where the ultrasonic transducers 2 and 3 are attached must be made thin. There is a possibility that a measurement error may be caused by the influence of the vibration of the pipe 1.

The ultrasonic wave has a much higher attenuation ratio in the gas than in the liquid. Therefore, if bubbles are mixed in the fluid, the attenuation of the ultrasonic waves becomes significantly larger than the attenuation caused by the suspended substances. As a result, there is a possibility that the measurement result indicating that the concentration of the suspended substance can not be measured or that the concentration is higher than the actual concentration may be generated.

Therefore, a defoamer type densitometer having a structure capable of removing bubbles contained in the fluid is considered. The volumetric concentration meter is used to put a fluid to be measured into a pressurized vesicle chamber at a predetermined sampling period, apply pressure to the fluid to be measured to remove bubbles, and then measure the concentration of the fluid to be measured. However, since this bubble concentration meter is a method of sampling the fluid to be measured every predetermined sampling period, the concentration of the fluid to be measured can not be continuously measured. In addition, there is a problem in terms of reliability because a mechanical moving mechanism is required to sample the fluid to be measured or apply pressure to the fluid to be measured.

In addition, the concentration meter using ultrasonic waves can not measure the concentration of the dissolved substance dissolved in the fluid because the ultrasonic dispersion attenuation due to the suspended substance contained in the fluid to be measured is used.

Thus, it is possible to reduce the labor of cleaning the suspended substances adhering to the piping in recent years, to measure the concentration of the dissolved substance dissolved in the fluid to be measured, and furthermore to continuously measure A microwave concentration meter with excellent performance is developed.

FIG. 11 shows a configuration example of a densitometer using microwaves.

In this microwave concentration meter, a microwave antenna 11 and a microwave receiving antenna 12 are arranged to face each other in a pipe 1 through which a fluid to be measured flows. The microwave emitted from the microwave oscillator 13 is transmitted to the phase difference measurement circuit 15 through the power splitter 14, the transmission antenna 11 and the in-pipe fluid reception antenna 12, A second path is directly introduced from the phase difference measuring circuit 15 to the phase difference measuring circuit 15. The phase difference measuring circuit 15 obtains the phase delay for the microwave through the second path of the microwave through the first path as a phase difference.

When the reference fluid (for example, tap water) is filled in the pipeline, the microwave is generated from the microwave oscillator, and the phase difference measurement circuit 15 measures the phase delay of the microwave through the existing fluid for the microwave received through the non- Measure &thetas; ₁ .

Next, a microwave is generated from the microwave oscillator 13 in a state where the pipe 1 is filled with the fluid to be measured, and the microwave is directly received from the microwave 13 through the power splitter 14 in the phase difference measuring circuit 15 The phase delay? ₂ of the microwave propagating through the fluid to be measured in the pipe is measured. Then, the phase difference? ₁ (? ₂ -? ₁ ) is compared with the previously measured phase delay? ₁ and the phase delay? ₂ obtained by the current measurement, and the phase difference?

Concretely, the concentration X is calculated by substituting the phase difference ?? for the calibration curve defined by the formula: X = a ?? + b. Also, a is the slope of the calibration curve, and b is the intercept of the calibration curve.

However, since the microwave concentration meter detects the phase delay of the microwave that changes depending on the concentration state of the fluid to be measured, the following problems arise.

12 shows a microwave W1 oscillated from the microwave concentration meter 13 and a microwave W2 having a phase delay? ₁ received by the microwave receiving antenna 12 through a reference fluid such as tap water, And a microwave W3 having a phase delay? ₂ received by the microwave receiving antenna 12 through the measurement fluid.

The phase delay? ₂ of the microwave W3 greatly varies depending on the concentration state of the fluid to be measured. When the fluid to be measured has a high concentration, the phase delay? ₂ may exceed 360 degrees to become the first rotation or second rotation angle.

For convenience, 0 ° ≤ θ ₂ ≤ 360 ° is defined as 0 ° rotation, 360 ° <θ ₂ ≤ 720 ° as the first rotation, 720 ° <θ ₂ ≤ 1080 ° as the second rotation, that is, (n-1) θ ₂ ≦ n × 360 ° will be referred to as (n-1) rotation. θ ₁ is assumed to be at the 0th rotation. n = -1, or 1, 2, 3, ... Lt; / RTI &gt;

As shown in FIG. 13, when the phase delay? ₂ of the microwave W4 is in the first rotation because the concentration of the fluid to be measured is high, the phase difference measuring circuit 15 outputs the apparent phase delay? ₂ ' . A measurement result indicating that the concentration of the fluid to be measured is low despite the high concentration is obtained.

When the diameter of the pipe 1 is large, the propagation path of the microwave becomes long, so that the phase delay? ₂ of the microwave W3 becomes large just as in the case of the high concentration of the fluid to be measured. It is also possible that the pipe 1 has a large diameter and the high surface phase delay θ ₂ of the fluid to be measured exceeds 720 ° and becomes an angle of the second rotation (720 <θ ₂ ≤ 1080 °).

The reference phase delay? ₂ is measured using the reference fluid as described above. To this phase delay θ ₁ as zero point and measuring microwave phase delay θ ₂ of the measured fluid passes. However, when the phase delay? ₁ at a certain point of time as shown in FIG. 14 is measured as a zero point data? ₁ at a value close to 0 ° and the tap water whose zero point is to be checked next is measured, The zero point phase delay? ₁ is drifted to be 0 deg. Or less, and the phase angle from the 0th rotation to the first rotation phase is apparently a large angle? ₁ close to 360 deg., So that the apparent zero point is largely drifted to the plus side It becomes unreasonable to become.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to accurately measure the concentration of a fluid to be measured from a low concentration to a high concentration and to accurately measure the concentration of a fluid to be measured flowing in the pipe of a large diameter, So that it is possible to prevent the unnecessary change in the number of revolutions even when the state of the microwave concentration is changed.

The microwave concentration meter of the present invention includes a measurement tube through which a fluid to be measured flows, a microwave generator that generates microwaves, and a microwave supplied from the microwave generator installed in the measurement tube, to the measured fluid flowing through the measurement tube A microwave receiver installed in the measuring tube so as to face the microwave transmitter and receiving the microwave transmitted from the microwave transmitter; and a microwave receiver for receiving the microwave generated from the microwave generator and the microwave receiver A phase difference detecting circuit for detecting a phase difference between the microwave and the microwave; and a phase difference detecting circuit for raising the value of the number of rotations n when the phase difference apparently fluctuating within an angular range of 360 ° is returned to the minimum angle side beyond the maximum angle of the angular range, And the number of revolutions to update circuit came back toward the maximum angle below the minimum angle of the group angular ranges make the value of the number of revolutions n, the measuring tube based on when the fluid flows through the reference of the phase difference detected by the phase difference detection circuit phase difference θ ₁ and the liquid to be measured are flowed into the measuring tube to measure the concentration of the fluid to be measured, the apparent phase difference? ₂ 'detected by the phase difference detecting circuit and the phase difference? ₂ ' A correction circuit for obtaining a phase difference ?? indicating a difference between a true phase difference? ₂ corresponding to the concentration of the fluid to be measured and the reference phase difference? ₁ from the rotation number n updated by the circuit, To a concentration signal indicating the concentration of the fluid to be measured, an operation mode setting unit for setting an operation mode, Groups is the number of revolutions n and the phase difference θ ₂ 'on the one surface when changing to a non-measuring operation by the movement change of the set operating mode from the concentration measuring operation of the measured fluid by the hold circuit of FIG hole.

According to the microwave concentration meter constructed as described above, the reference phase difference? ₁ representing the phase delay of the microwave relative to the reference fluid is obtained by flowing the reference fluid through the measuring tube and measuring the phase difference by the phase difference detecting circuit. When measuring the concentration of the fluid to be measured, the fluid to be measured flows into the measuring tube and the apparent phase difference? ₂ ', which is the phase delay of the microwave relative to the fluid to be measured, is measured by the phase difference detecting circuit. In the correction circuit, the phase difference ?? representing the difference between the true phase difference? ₂ and the reference phase difference? ₁ from the above-mentioned rotation number n updated by the rotation number update circuit in accordance with the apparent phase difference? ₂ 'and the apparent phase difference? ₂ ' It becomes. In the signal change circuit, the phase difference [Delta] [theta] is converted into a concentration signal representing the concentration of the fluid to be measured.

Here, after the microwave concentration meter is changed from the concentration measurement operation of the measured fluid to the non-measurement operation, the measurement tube is likely to be temporarily empty. For example, when the zero point adjustment is performed, the measured fluid in the measuring tube is discharged to introduce the reference fluid such as tap water into the measuring tube and temporarily empty. In addition, when the sludge is discharged to the sludge tank through the measuring tube intermittently, the measuring tube may be empty except when the sludge passes.

When the measurement of the concentration of the fluid to be measured is resumed, the rotation number n is determined from the finally measured apparent phase difference? ₂ 'and the initially measured apparent phase difference? ₂ ' after the resumption. If the rotation number n is updated by the apparent phase difference &amp;thetas; ₂ 'of the microwave passing through the empty measuring tube when the concentration measurement is not performed, there is a possibility that the rotation number n changes greatly from the reality to a remote value. When the concentration is measured based on the apparent phase difference? ₂ 'and the rotation number n which are low in reliability when the measurement of the concentration of the fluid to be measured is resumed, a measurement value quite different from reality is likely to be calculated.

This microwave concentration meter allows measurement values far away from reality to be calculated when the measurement of the concentration of the fluid to be measured is resumed by holding the rotation number n and the apparent phase difference? ₂ 'at a value immediately before the change from the concentration measurement operation to the non- Can be prevented.

When the microwave densitometer of the present invention returns from the "maintenance mode" to the "measurement mode" or when the "external synchronized mode" is instructed and the measurement operation is started, the phase of the apparent phase comparing the delay θ ₂ 'and this measure the phase delay on the surface θ _2' to determine the value of the rotational speed n.

According to this microwave concentration meter, when returning from the "maintenance mode" to the "measurement mode" or when the measurement operation is started in the "external cooperating mode", the apparent phase delay θ ₂ 'held in the hold circuit, this is determined on the phase delay θ ₂ 'the value of the number of revolutions n, based on the result of the comparison is a comparison.

The microwave concentration meter of the present invention is constituted by a condition setting unit for setting a high concentration value X _max that can not occur as an object to be measured and a minus concentration value X _min that can not occur even when the zero point drifts, A correct rotation number n is obtained by comparing with the value X _max or the minus concentration X _min, and the concentration of the fluid to be measured is calculated using the rotation number n.

According to this microwave concentration meter, the high concentration value X _max that can not occur as the measurement object and the negative concentration value X _min that can not occur even when the zero point drifts are set in advance. Then, the measured concentration calculated value in the normal concentration measurement state is compared with the high concentration value X _max and the negative concentration value X _min , and a proper number of revolutions n is obtained. The concentration of the fluid to be measured is calculated using the number of revolutions n.

Hereinafter, embodiments of the present invention will be described.

FIG. 1 is a configuration diagram of a microwave concentration meter according to this embodiment.

The microwave concentration meter is arranged such that the concentration measuring pipe 20 is disposed between the upstream pipe 21 and the downstream pipe 22 through the partition 23 and 24. The concentration measuring pipe (20) is provided with a water supply valve (26) and a drain valve (27). A water pipe 28 for introducing a reference fluid such as tap water is connected to the water supply valve 26 and a water discharge pipe 29 is connected to the water discharge valve 27.

The concentration measuring tube 20 is provided with an opening window for entering and exiting microwaves, respectively, at positions facing the opponent with observations thereon. An antenna mounting plate is attached to the opening window through airtight seal packing. The antenna mounting plate is closely attached to the transmission antenna 31 and the reception antenna 32 through an insulator. The insulation of the antenna mounting plate is made of fiber-reinforced plastic (FRP), vinyl chloride resin, or other insulating material. The transmission system of this densitometer is provided with a microwave oscillator 33 for generating a microwave and the output of the microwave oscillator 33 is sent to the transmission antenna 31 through the power splitter 34.

On the other hand, the reception system of the densitometer includes a phase difference measuring circuit 35, a phase difference correcting circuit 36, a speed conditioner 37, a signal converting circuit 38 and an operation mode setting device 39 have.

The phase difference measurement circuit 35 receives a microwave reception wave from the reception antenna 32 and a part of the microwave transmission wave from the power splitter 34 as a reference signal and outputs the reception wave of the reception wave to the microwave transmission wave The phase delay of the phase is measured.

The garage difference correction circuit 36 performs a process to be described later to obtain a true phase delay from the apparent phase delay and calculates a phase difference ?? between the true phase delay and the reference phase delay.

FIG. 2 shows functional blocks of the phase difference correction circuit 36.

The phase difference correction circuit 36 includes a rotation number updating section 41 for determining the rotation number n and a true value detecting section 42 for obtaining the true phase delay? ₂ from the rotation number n determined by the rotation number updating section 41 A difference detecting section 43 for detecting a difference between the true phase delay? ₂ and the reference phase delay? ₁ , a mode judging section 44 for judging the operation mode, a validity judging section 45 for judging validity of the measured concentration ).

Revolution speed condition setting device 37 is, 0 ° ~360 ° range above and below the range of the angle range and the like can not take place as the measuring object a high concentration value X _max and the zero point may be such that can not occur a drift The minus concentration value X _min and the arbitrary number of rotations n are manually determined.

The signal conversion circuit 38 has the calibration curve data shown in Fig. 8 set therein, and the density value corresponding to the phase difference ?? input from the phase difference correction circuit 36 is obtained based on the calibration curve graphed data, And outputs the corresponding current signal.

The operation mode setting unit 39 is provided with a &quot; measurement mode &quot; for performing normal concentration measurement, a &quot; maintenance mode &quot; for performing auxiliary operations such as zero point adjustment, And the &quot; external interlocking mode &quot;

Here, the calculation principle of the true phase delay? _{2 in} the phase difference compensation circuit 36 will be described.

As shown in FIG. 7, the apparent phase delay? ₂ 'varies within a range of an angle range of 360 °. The predetermined range from 0 DEG to 360 DEG in the angular range of 0 DEG to 360 DEG is set as the lower range and the predetermined range from 360 DEG to 0 DEG in the angular range from 0 DEG to 360 DEG is set as the upper range. For example, a range of 0 ° to 120 ° is set as the lower range, and a range of 240 ° to 360 ° is set as the upper range.

The apparent phase delay &amp;thetas; ₂ 'is not continuous but is set at a short time interval (5 seconds interval in the present embodiment). If the apparent phase delay θ ₂ 'at a certain point exists in the upper range and the apparent phase delay θ ₂ ' exists in the lower range at the next point, the rotation number n is changed to n = n + 1. If the apparent phase delay? ₂ 'at a certain point exists in the lower range and the apparent phase delay? ₂ ' exists in the upper range at the next point of time, the rotation number n is changed to n = n-1 . Using this number of rotations n, the true phase delay? ₂ 'is calculated.

The change of the number of revolutions n based on such a condition is performed in the range of the same number of revolutions n (for example, the number of revolutions per minute) in the apparent phase delay &amp;thetas; ₂ ' in the n = 0 is true, the phase delay θ ₂ in the range of 0 ° ~360 °), in the range below the above range, or the developer to change significantly in the above range in the following ranges (a concentration change, a temperature change, etc.) it is actually It assumes that it does not happen. For example, if the apparent phase delay &amp;thetas; ₂ changes from the upper range to the lower range or from the lower range to the upper range within 5 seconds, it is determined that the rotation number n has changed.

Next, the operation of the densitometer of the present embodiment configured as described above will be described with reference to FIGS.

An arbitrary operation mode is preset from the operation mode setter 39 to the phase difference correction circuit 36. [ For example, when the equipment is subjected to maintenance inspection, a &quot; maintenance mode &quot; is set. When the sludge contained in the tank reaches a predetermined water level, the pump is driven to perform intermittent operation such as discharging sludge from the tank to the pipe 21 , The "external linkage mode" is set.

In this embodiment, the mode judging unit 44 judges the operation mode set in the phase difference correcting circuit 36 at the start of operation (step S1). When the &quot; measurement mode &quot; is set, the processes of steps S2 to S9 are executed.

If the reference phase delay? ₁ is not held in the difference detector 43 of the phase difference correction circuit 36, the reference phase delay? ₁ is measured in advance. In the measurement of the reference phase delay? ₁ , after the partition sides 23 and 24 are closed, the drain valve 27 is opened to discharge the measurement fluid such as sludge in the pipe 20 and then the water supply valve 26 is opened After the tap water is supplied to clean the dirt in the tube 20, the drain valve 27 is closed to fill the tube 20 with the tap water.

After the tap water is filled as described above, a microwave signal is generated from the microwave oscillator 33 as shown in FIG. 9 (a). This microwave is transmitted from the transmitting antenna 31 through the power splitter 34 and propagates through the tap water in the measuring tube 20 and is received by the receiving antenna 32. The received wave to be received is sent to the phase difference measuring circuit 35.

A part of the microwave transmitting wave is sent from the power splitter 34 to the phase difference measuring circuit 35. [ The phase difference measurement circuit 35 measures the reference phase delay? ₁ with respect to the reference fluid by comparing the microwave transmission wave with the microwave reception wave. And sends the measured reference phase delay? ₁ to the phase difference correction circuit 36.

The phase difference correction circuit 36 stores the reference phase delay? ₁ input from the phase difference measurement circuit 35 in the difference detection section 43. [ In the phase difference correction circuit 36, n = 0 is set as the initial value of the rotation number from the rotation number condition setting device 37. [

Next, the apparent phase delay? ₂ 'of the fluid to be measured is measured (step S2). That is, the drain valve 27 is opened to discharge the tap water in the measuring pipe 20, and then the partitioning walls 23 and 24 are opened to flow the measuring fluid containing the measuring material. In this state, a microwave signal is emitted from the microwave oscillator 33. The microwave signal is sent to the transmission antenna 31 and the phase difference measuring circuit 35 through the power splitter 34 as described above.

9B, when the microwave emitted from the transmission antenna 31 propagates the fluid to be measured in the concentration measuring pipe 20 and reaches the receiving antenna 32, the receiving antenna 32 detects the concentration of the fluid to be measured And outputs a microwave signal having a phase delay in accordance with the phase difference. The phase measurement circuit 35 measures the apparent phase delay? ₂ 'of the microwave signal having the phase delay according to the concentration of the fluid to be measured. In this way, the microwave is sent to the measuring fluid in a state in which the measuring fluid containing the measuring substance is flowing, and the apparent phase delay? ₂ 'is measured in a short time period (for example, every 5 seconds).

When the apparent phase delay? ₂ 'is measured, the rotation number n is determined based on the proo chart shown in FIG. 5 (step S3). That is, the upper range, the lower range and the initial value n = 0 of the number of revolutions are read from the revolute condition setter 37. The apparent phase delay? ₂ 'is received from the phase difference measuring circuit 35 and it is determined whether or not the apparent phase delay? ₂ ' is within the upper range (step T1). If the apparent phase delay &amp;thetas; ₂ 'exists in the upper range, for example, it is determined whether or not θ ₂ ' after 5 seconds falls within the lower range (step T 2). When the angle θ ₂ 'after 5 seconds falls within the lower range, the apparent phase delay θ ₂ ' changes from the upper range to the lower range within 5 seconds as shown by the change A shown in FIG. 7, n + 1 (step T3).

If the apparent phase delay? ₂ 'received from the phase difference measuring circuit 35 does not fall within the upper range, it is judged whether or not the corresponding? ₂ ' exists in the lower range (step T4). If θ ₂ 'exists in the lower range, it is determined whether or not θ ₂ ' measured after 5 seconds falls within the upper range (step T 5). When θ ₂ 'measured after 5 seconds falls within the upper range, since the angle θ ₂ ' changes from the lower range to the upper range within 5 seconds as shown by the change B shown in FIG. 7, -1 (step T6).

In other cases, the rotation number n is not changed.

When the rotation number n is determined in step S3, the true value detection section 42 calculates the true phase delay? ₂ based on the expression (1) (step S4).

The difference detector 43 then calculates the phase difference ?? based on the equation (2) (step S5).

The thus obtained [Delta] [theta] is input to the signal conversion circuit 38 to calculate the concentration X (step S6).

Here, when the concentration measuring pipe 20 is temporarily empty during the measurement operation in the &quot; measurement mode &quot; or the &quot; external interlocking mode &quot;, there is a high possibility that the rotation number n is unnecessarily changed.

Here, in the process of step S7, the validity judging unit 45 judges whether the concentration calculation value X is a valid value based on the proofer Chad of FIG. That is, when the rotation number n satisfies the condition of n? 1 and the concentration calculation value X is X? X _max , the rotation number n is instructed to change the rotation number n to n = n-1. The number of revolutions n satisfies the condition of n <0, and instructs the addition concentration calculated value X so as to change the number of revolutions n to n = n + 1 for X≤ if X _min, rotation number updating section (41).

If X &lt; X _max in n? 1, the rotation number n is not changed. If n &lt; 0 and X &gt; X _min , the rotation number n is not changed. Also, even when n = 0, the rotation number n is not changed.

In step S7, the process is returned to step S4 as long as the number of rotations n is changed in this manner, and the concentration X is again calculated using the number of rotations n after the change. Then, at the point in time when the change of the rotation number n is finished, the density calculation value X at that time is output as the density measurement value (step S9). And outputs a current signal according to the measured concentration value. For example, if the concentration measurement range is 0 to 10%, a corresponding 4 to 20 mA current signal is output.

On the other hand, if it is determined in step S1 that the measurement mode is other than the &quot; measurement mode &quot;, it is determined whether or not it is again the &quot; maintenance mode &quot;. In the case where it is judged as the "maintenance mode", the processes of the steps S11 to S12 are executed until the "measurement mode" is set. After the "measurement mode" is set, the processes of the steps S13 and S14 are executed, Goes.

In the processing of step S11, the rotation number n output from the rotation-axis finishing section 41 and the apparent phase delay? ₂ 'used in the true value detection section 42 are set to a value immediately before entering the non-measurement operation ₂ ', the number of revolutions n). Then, it is determined whether or not the &quot; measurement mode &quot; is set at a predetermined cycle (step S12).

When the mode judging unit 44 detects the change from the "maintenance mode" to the "measurement mode", the apparent phase delay θ ₂ 'is measured in the same manner as the step S2 (step S13). Using the measured apparent phase delay? ₂ 'and the apparent phase delay? ₂ ' held in step S11, processing based on the proofer Chad of FIG. 5 is executed to determine the number of revolutions n (step S14). At this time, θ ₂ 'measured in step S 13 is treated as θ ₂ ' after 5 seconds in FIG.

When the first rotation number n is determined immediately after the change from the "maintenance mode" to the "measurement mode" in this manner, the flow proceeds to step S2 to carry out the above-mentioned concentration measurement.

If it is determined in step S1 that the measurement mode is not the &quot; measurement mode &quot;, and if it is determined in step S10 that the mode is not the &quot; maintenance mode &quot;, then the &quot; external interlocking process &quot; It is determined whether or not a signal indicating that the fluid to be measured flows is received (step Q1). In the case of the present embodiment, it is determined whether or not a pump operation signal of the pump for discharging the sludge of the sludge tank to the pipe 21 has been received. While the pump operation signal is being received, the fluid to be measured flows.

If the pump operation signal is received in step Q1, the process proceeds to step S2 to execute the concentration measurement operation. On the other hand, if the pump operation signal is not received at the judgment of the step Q1, the rotation number updating unit 41 and the true value detecting unit 43 of the phase difference correcting circuit 36, in order to prevent unnecessary fluctuation of the rotation number n, And the apparent phase delay? ₂ 'and the rotation number n output by the phase comparator 31 (step Q2). When the signal indicating that the fluid to be measured is flowing, that is, the pump operation signal is received (step Q3) in the state where the ₂ &amp;thetas;'and the rotation number n immediately before entering the non-measurement operation are held, It is measured on the phase delay θ ₂ '(step Q4). Next, the determining procedure control the number of revolutions according to Chad n shown in FIG. 5 by using a one phase delay on the apparent measurement θ ₂ 'and step one apparent phase delay (θ ₂ on hold in the process of Q2'). At this time, the processing θ ₂ as measured at the step Q4 'to θ ₂ of 5 seconds.

If the number of rotations n is determined in the process of step Q5, the process proceeds to step S2 for displaying on the proofer Chad of FIG. 3, and the concentration measurement is performed.

As described above, according to the microwave densitometer of this embodiment, from the phase delay of the microwave signal obtained under the measurement conditions such as the phase delay of the microwave signal obtained by transmitting the microwave from the transmitting side during the measurement of the reference fluid and the measurement condition of the fluid to be measured, And the concentration of the fluid to be measured is obtained from the phase difference ??. This makes it possible to measure the concentration without being influenced by adhesion of suspended substances contained in the fluid to be measured and bubbles in the fluid to be measured, Even if there are substances dissolved in the solution, the concentration can be measured. In addition, since there is no mechanical mechanism, high reliability can be maintained in the long term.

According to the microwave concentration meter of this embodiment, the lower range and the upper range are set in the angular range of 0 ° to 360 °, and the range in which the apparent phase delay θ ₂ 'currently belongs is compared with the range in the next round, Since hangeotyi that can accurately determine the number of revolutions of the phase delay θ ₂ 'on the surface, the phase delay is even more than beyond at 1 rotation to 360 ° is possible to accurately measure the concentration of a high concentration measuring fluid, and for the concentration of the large-diameter detection Concentration can also be accurately measured in a tube.

According to the microwave concentration meter of the present embodiment, the high concentration threshold value X _max and the minus concentration threshold value X _min are set in the revolution speed conditioner 37, and the concentration calculation value X Is compared with the high concentration threshold value X _max or the minus concentration threshold value X _min to determine the optimum number of rotations according to the concentration or the like of the present measuring fluid. Thus, it is possible to always maintain the accurate number of rotations and to obtain a reliable concentration measurement value have.

According to the microwave concentration meter of the present embodiment, a period during which the wave measuring fluid does not flow during the "maintenance mode" and the "external synchronized mode" by inputting the operation mode from the operation mode setter 39 is an apparent phase delay θ ₂ 'And the number of revolutions n is held at the previous value to prevent unnecessary fluctuations in the number of revolutions, and if the measured fluid does not flow, a new number of revolutions n is determined using the held θ ₂ ' and the number of revolutions n , It is possible to avoid an abnormally large or small retardation value obtained by measurement even if an air layer is temporarily formed in the tube for concentration detection at the time of maintenance or external interlocking start, .

The present invention is not limited to the above-described embodiments, but the present invention can be similarly carried out as follows.

(a) In each of the above-described embodiments, the measurement was made while the suspended material was flowing. However, the concentration may be measured in the stationary state, and the tap water is used as the reference fluid.

The measuring pipe 20 is disposed so as to be sandwiched between the upstream pipe 21 and the downstream pipe 22. For example, when a container for receiving fluid is installed in the flow pipe of the measured fluid or when a bypass pipe is provided , The above-described technique is applied to these vessels and bypass pipes, and this is also included in the scope of the present invention.

(b) In the above-described embodiment, the measurement of the phase difference is explained by the measurement method of 0 to 360 °. However, the number of rotations may be determined by setting the upper range and the lower range in the angle range of -180 ° to + 180 ° .

(c) In the above embodiment, n = 0 is set at zero point adjustment, but the present invention is not limited to this. For example, when n = 1, processing of? ₂ =? ₂ '+ .

(d) The number of revolutions update unit updates the number of revolutions n by determining the range in which the apparent phase delay &amp;thetas; ₂ 'belongs by setting the upper range and the lower range in the angle range, Maybe. For example, when measuring the concentration of the fluid to be measured, the apparent phase delay? ₂ 'is continuously received from the phase difference measuring circuit to differentiate the apparent phase delay? ₂ ' to detect the increase / decrease direction of? ₂ '. When the apparent phase delay θ ₂ 'increases, the rotation number n is increased by 1 when it passes the maximum value of the angle range of 360 °. When the apparent phase delay &amp;thetas; ₂ &apos; is reduced and the minimum value of the angular range 360 is passed, the number of rotations n is decreased by one.

Claims (15)

A concentration meter for measuring a concentration of the fluid to be measured from a phase delay of a microwave that has passed through a fluid to be measured, comprising: a measurement tube through which the fluid to be measured flows; a microwave generator for generating the microwave; A microwave transmitter for transmitting the microwave supplied from the microwave generator to the fluid to be measured flowing through the measuring tube; and a microwave transmitter provided in the measuring tube so as to be oriented with respect to the microwave transmitter, A phase difference detecting means for detecting a phase difference between the microwave generated by the microwave generator and the microwave received by the microwave receiver; The maximum angle A rotation number updating means for increasing the value of the rotation number n when the rotation angle is shifted to the minimum angle side and decreasing the rotation number n when the phase difference is smaller than the minimum angle of the angle range and returning to the maximum angle side; A reference phase difference? ₁ , which is a phase difference detected by the phase difference detecting means when the fluid flows, and a phase difference between the reference phase difference? ₁ and the phase difference detected by the phase difference detecting means when measuring the concentration of the fluid to be measured, a phase difference θ ₂ of a pointed reference phase difference θ ₁ above and a phase difference θ ₂ corresponding to the concentration of the one measured fluid from the above-mentioned number of revolutions n updated by the rotation number updating means in accordance with 'the art the phase difference θ ₂ on the apparent " A correction means for obtaining a phase difference [Delta] [theta] representing a difference and a phase difference [theta] And an operation mode setting means for setting the operation mode of the operation mode setting means in accordance with the operation mode set by the operation mode setting means, And holding means for holding the apparent phase difference? ₂ '. The apparatus according to claim 1, wherein the operation mode setting means includes at least two operation modes including a "measurement mode" for performing a normal measurement operation and a "maintenance mode" for blocking a fluid to be measured flowing through the measurement tube for maintenance And the hold means holds the rotation number n and the apparent phase difference? ₂ 'at that time when the "repair board" is set in the operation mode setting means. 3. The apparatus according to claim 2, wherein said rotation number updating means updates said rotation number held by said holding means and said apparent phase delay when said operation mode is changed from said & And the rotation number n is determined at an apparent phase delay (? ₂ ') measured by the phase difference detection means for the first time after changing from the "maintenance mode" to the "measurement mode". 2. The apparatus according to claim 1, wherein the operation mode setting means includes at least two measurement modes including a &quot; measurement mode &quot; for performing a normal measurement operation and an &quot; external interlocking mode &quot; for performing a measurement operation only while the measured fluid is flowing through the measurement tube ( ₂ &apos; ₂ &apos;) and the apparent phase difference (&amp;thetas; ₂ &apos;) when the &quot; external interlocking mode &quot; is indicated by the operation mode setting means and the concentration measurement is stopped, Of the microwave concentration meter. 5. The image forming apparatus according to claim 4, wherein the rotation number updating means updates the number of rotations and the number of revolutions that have been held by the holding means when the &quot; external linkage mode &quot; And said apparent phase delay and the value of said rotation number n are first determined to an apparent phase delay? ₂ 'measured by said phase difference detection means after the concentration measurement is resumed. The apparatus according to claim 1, wherein the operation mode setting means comprises: a "measurement mode" for performing a normal measurement operation; a "maintenance mode" for blocking a fluid to be measured flowing through the measurement tube for maintenance; Three or more operation modes including an &quot; external interlocking mode &quot; for performing a measurement operation only while flowing through one measuring tube are selectively set, and the above-mentioned holding means is provided for, when the above- When the &quot; external motion mode &quot; is indicated and the farming measurement is stopped, the above-mentioned rotation number n and the above-mentioned apparent phase difference? ₂ 'are held. 7. The apparatus according to claim 6, wherein said rotation number updating means updates said rotation number held by said hole means when said operation mode is changed from said "maintenance mode" to said "measurement mode" The value of the above-mentioned rotation number n is determined by the apparent phase delay &amp;thetas; ₂ 'measured by the above-mentioned phase difference detection means after the phase delay on the phase difference between the phase difference And when the concentration measurement is resumed, the above-described number of revolutions held by the holding means and the above-mentioned apparent phase delay are measured again after the density measurement is resumed, And the value of the rotation number n is determined by the apparent phase delay? ₂ '. The method of claim 1, wherein the measured fluid can not beat inversion X _max and the zero point may not occur a drift set up a low concentration value X _min key condition setting means, and the normal measured at density measurement state by happen concentration values and Further comprising validity judging means for comparing said high concentration value X _max or said low concentration value X _min and instructing said revolution number updating means to change the revolution number when said concentration value is not valid. Densitometer. The method of claim 8, wherein the validity judgment unit includes more instructions to make a is greater above the number of revolutions can rotate the updating means n than the high concentration value X _max is the aforementioned concentration values above, and a low concentration value X _min is the concentration values above And instructs the number-of-rotations updating means to increase the number of rotations n when the number of rotations is small. 2. The image processing apparatus according to claim 1, wherein the correcting means comprises: true value detecting means for obtaining a true phase difference? ₂ from the apparent phase difference? ₂ ' From the reference phase difference? ₁ and the above-mentioned true phase difference? ₂ , the difference detection means Of the microwave concentration meter. The apparatus according to claim 1, characterized in that the number of revolutions updating means is set such that a predetermined range is set as a lower range from a minimum angle to a maximum angle of the angular range and a predetermined range is set as the above range, the phase difference on the one surface from said phase difference detecting means θ ₂ apparent on the in the range to which it belongs, the phase difference θ ₂ on the surface on which been accepted at a predetermined time interval of the time, and the next point in the And compares the range to which the phase difference? ₂ 'belongs to update the rotation number n. 12. The method of claim 11, wherein the rotation number updating means, in the apparent phase difference θ ₂ on the "belongs to a range below the one and the phase difference on the surface θ ₂ in the following point, that the above range, at some point The above-mentioned apparent phase difference? ₂ 'at a certain point belongs to the upper range and the apparent phase? ₂ ' at the next time point falls in the lower range described above And the rotation number n is added by &quot; 1 &quot; The image forming apparatus according to claim 1, wherein the rotation number updating means includes a tendency detecting means for continuously receiving the apparent phase difference? ₂ 'from the phase difference detecting means and continuously detecting an increase / decrease direction of the apparent phase difference? ₂ ' When the apparent phase difference &amp;thetas; ₂ 'is detected by the tendency detecting means, the value of the rotation number n is increased when the apparent phase difference &amp;thetas; ₂ ' exceeds the maximum angle of the angular range, And when the apparent phase retardation? ₂ 'is detected by the detection means, the rotation speed n is lowered when the apparent phase difference? ₂ ' exceeds the minimum angle of the angular range. Densitometer. The rotation angle updating device according to claim 1, wherein the rotation number updating means sets the predetermined range to a lower range from a minimum angle of the angle range to a maximum angle side, Wherein the apparent phase difference &amp;thetas; ₂ ' from the phase difference detection means is taken in a time interval and the apparent phase difference &amp;thetas; ₂ 'at a certain point belongs to the lower range described above, When the phase difference &amp;thetas; ₂ 'belongs to the above upper range, the rotation number n is subtracted by &quot; 1 &quot;, and the apparent weft difference &amp;thetas; ₂ ' at a certain point belongs to the above- And when the apparent phase delay? ₂ 'falls within the lower range, the rotation number n is added by "1", and the correction means adds the apparent phase difference? from θ ₂ 'can rotate with the n and true value detecting means for obtaining a true phase difference θ ₂ by the formula below, From the reference phase difference? ₁ and the true phase difference? ₂ , the difference detection means obtains the phase difference ?? The operation mode setting means includes a "measurement mode" for performing a normal measurement operation, a "maintenance mode" for blocking a measurement fluid flowing through the measurement pipe for maintenance, and a "maintenance mode" Three or more operation modes including an &quot; external interlocking mode &quot; for performing a measurement operation are selectively set, and when the &quot; maintenance mode &quot; is instructed or the &quot; external interlocking mode &quot; Holds the rotation number n and the apparent phase difference &amp;thetas; ₂ 'when the measurement is stopped, and the rotation number updating means changes the rotation number from the "maintenance mode" to the "measurement mode" , The rotation number and the apparent phase delay which are held by the holding means are changed to the &quot; measurement mode &quot; in the &quot; maintenance mode &quot; With a phase delay θ ₂ 'on the surface decide the value of the number of revolutions n, the "external interlocking mode" is indicated and also the concentration measurement is time, the rotational speed and phase on the surface which has been held by said holding means to resume And the value of the number of revolutions n is set to the apparent phase delay? ₂ 'measured by the phase detecting means for the first time after the delay and the concentration measurement are resumed. The apparatus according to claim 14, further comprising: condition setting means for setting a high concentration value X _max that can not occur in the fluid to be measured and a low concentration value X _min that can not occur even at zero point drift; the high concentration value X _max or a microwave meter for the time validity determining means indicative of a change in the number of revolutions to the rotation number updating means compares the low concentration value X _min not in the concentration values is valid characterized by further comprising.